Creep-rupture life of Douglas-fir under cyclic environmental conditions

Abstract According to the microstructural evolution during longterm thermal exposure at 1100 °C, the creep rupture life of Ni-based single crystal superalloys at 980 °C/270 MPa was evaluated. The microstructure was characterized by means of scanning electron microscopy, X-ray diffraction and related image processing methods. The size of γ’ precipitates and the precipitation amount of topologically close-packed increased with the increase in thermal exposure time, and coarsening of the γ’ precipitates led to the simultaneous increase of the matrix channel width. The relationship between the creep rupture life and the lattice misfit of γ/γ’, the coarsening of γ’ precipitate and the precipitation of TCP phase are systematically discussed. In addition, according to the correlation between γ’ phase evolution and creep characteristics during thermal exposure, a physical model is established to predict the remaining creep life.

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Long Term Creep Properties of a Die-Cast Mg-Al-Ca Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.163 ◽

2007 ◽

Vol 561-565 ◽

pp. 163-166

Author(s):

Yoshihiro Terada ◽

Tatsuo Sato

Keyword(s):

Creep Rate ◽

Magnesium Alloys ◽

Cast Alloy ◽

Rupture Life ◽

Testing Temperature ◽

Creep Rupture ◽

Die Cast ◽

Cast Magnesium Alloys ◽

Term Creep ◽

Cast Magnesium

Creep rupture tests were performed for a die-cast Mg-Al-Ca alloy AX52 (X representing calcium) at 29 kinds of creep conditions in the temperature range between 423 and 498 K. The creep curve for the alloy is characterized by a minimum in the creep rate followed by an accelerating stage. The minimum creep rate (ε& m) and the creep rupture life (trup) follow the phenomenological Monkman-Grant relationship; trup = C0 /ε& m m. It is found for the AX52 die-cast alloy that the exponent m is unity and the constant C0 is 2.0 x 10-2, independent of creep testing temperature. The values of m and C0 are compared with those for another die-cast magnesium alloys. The value m=1 is generally detected for die-cast magnesium alloys. On the contrary, the value of C0 sensitively depends on alloy composition, which is reduced with increasing the concentration of alloying elements such as Al, Zn and Ca.

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Reliability assessment of creep rupture life for Gr. 91 steel

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2013.05.013 ◽

2013 ◽

Vol 51 ◽

pp. 1045-1051 ◽

Cited By ~ 20

Author(s):

Woo-Gon Kim ◽

Jae-Young Park ◽

Seon-Jin Kim ◽

Jinsung Jang

Keyword(s):

Rupture Life ◽

Reliability Assessment ◽

Creep Rupture

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Dependence of creep rupture life on primaryγ′ of a liquid metal cooling directionally solidified nickel-based superalloy

International Journal of Cast Metals Research ◽

10.1179/1743133612y.0000000043 ◽

2013 ◽

Vol 26 (3) ◽

pp. 134-137

Author(s):

K Zhao

Keyword(s):

Liquid Metal ◽

Rupture Life ◽

Creep Rupture ◽

Directionally Solidified ◽

Nickel Based Superalloy ◽

Liquid Metal Cooling

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CREEP RUPTURE LIFE OF PRE-STRAINED SUPERALLOY N07080

International Journal of Advanced Research ◽

10.21474/ijar01/13665 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1167-1176

Author(s):

Omer Beganovic ◽

Keyword(s):

Stress Concentration ◽

Grain Boundaries ◽

Rupture Life ◽

Warm Rolling ◽

Creep Rupture ◽

Cavity Nucleation ◽

Standard Heat ◽

Creep Cavity ◽

Heat Treated

The creep of the pre-strained superalloy N07080 is described in this work. The pre-strain was achieved by warm rolling at 1050 oC.-The warm rolling was performed due to additional strengthening, i.e increasing of the superalloy hardness.-The pre-strain drastically reduces the creep rupture life of the superalloy compared to the creep rupture life of the standard heat treated superalloy.-The drastic reductionof the creep rupture life is result of rapid creep cavity nucleation on stress concentration sites along primary grain boundaries of the pre-strained superalloy.-Recrystallization eliminates potential sites for rapid cavity nucleation and prolongates the creep rupture life.

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